Prep the chicken: Halve breasts horizontally to make 4 thin cutlets. Pat dry.
Season both sides with salt, pepper, garlic powder, and onion powder.
Sear: Heat 1 tablespoon olive oil in a large skillet over medium-high. Add chicken and cook 3–4 minutes per side until golden and just cooked through. Transfer to a plate and tent loosely with foil.
Sauté aromatics: Reduce heat to medium.
Add remaining 1 tablespoon olive oil, then the garlic. Cook 30–60 seconds until fragrant, not browned.
Build the sauce: Stir in lemon zest, lemon juice, broth, and Dijon. Scrape up browned bits from the pan.
Simmer 2–3 minutes to reduce slightly.
Finish: Whisk in butter (if using) for a glossy finish. Add capers or red pepper flakes if you like.
Return chicken: Nestle the chicken back into the sauce and simmer 1 minute to warm through. Sprinkle with parsley.
Serve: Spoon sauce over the chicken.
Great with steamed asparagus, a spring salad, or quinoa.